(a) Field of the Invention
The present invention relates to a signal detection method and a receiving apparatus in a multiple input multiple output (MIMO) system. More particularly, the present invention relates to a signal detection device in a MIMO system using a spatial multiplexing (SM) method.
(b) Description of the Related Art
A fourth generation mobile communication-based wireless communication system requires high-speed data services for images and packets rather than services based on voice. Accordingly, a multiple input multiple output (MIMO) system is being spotlighted since the MIMO system uses a spatial multiplexing method in which high-rate data transmission can be performed by transmitting multiple data streams (here, each stream is also referred to as a “layer”) to satisfy such a requirement. In the MIMO system using the spatial multiplexing method, transmitting antennas respectively transmit data layers including different pieces of information, and a receiving terminal separates the transmitted data layers. A conventional maximum likelihood (ML) signal detection method for detecting a transmission signal vector having ML metric values of available combinations of transmission signal vectors to detect a transmission signal has optimum performance. However, the conventional ML signal detection method may not be realized since complexity is problematically increased according to the number of transmitting antennas and the number of constellation points. Accordingly, a linear signal detection method reducing the complexity (e.g., a zero forcing (ZF) method and a minimum mean square estimator (MMSE) has been suggested, but performance thereof is deteriorated compared to the ML method. In addition, non-linear signal detection methods include an ordered successive interference cancellation (OSIC) method that is known as a vertical Bell Lab layered space time (VBLAST) method. The VBLAST method may be simply realized, and performance thereof is improved compared to the performance of the ZF and MMSE methods but is not greater than the ML method.
Associated technology relates to a signal detection method in a multiple transmitting/receiving antenna system using the spatial multiplexing method. To detect a signal in the MIMO system, a received signal is detected in a ZF method, and a first detection section is established from the detected signal. The received signal is detected in the ML method in the first detection section, and a second detection section is established from the signal detected in the ZF method and the signal detected in the ML method. The received signal is detected in the ML method in the second detection section, and a final value is established. Accordingly, while this conventional art has lower complexity than the ML method and higher performance than the ZF method and the MMSE method, it has lower performance than the ML method.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.